Recent wireless communications research has examined the benefits of splitting the conventional cells in wireless cellular communications into small cells for supporting the growing wireless network traffic. Small cells can coexist with neighboring small cells while sharing the same spectrum resources, and are thus an important potential strategy for accommodating wireless network traffic growth. Small cells are also sometimes referred to as “femto” cells in the context of the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) wireless standard; although the general terminology “small” cells is used throughout the present disclosure. However, small cells pose new challenges, including interference coordination, backhaul complexity, and increased network infrastructure cost.
Small cell networks are expected to be privatively owned. Therefore it is important to enable usage flexibility and the freedom of investment in the new network entities (e.g., gateways and servers) and the network infrastructures (e.g., switches and optical fiber) by the private owners of small cells. While a plethora of studies has examined advanced enhanced Node B (eNB) resource management, the implications of small cell deployments for backhaul gateways have largely remained unexplored. Generally, backhaul access networks that interconnect small cell deployments with LTE gateways can employ a wide variety of link layer (L2) technologies, including SONET/SDH, native Ethernet, and Ethernet over MPLS. In order to accommodate these heterogeneous L2 technologies, cellular LTE network interfaces, such as SI and X2 interfaces, are purposefully made independent of the L2 technology between small cell deployments and gateways. Due to the independent nature of L2 technologies, a dedicated link with prescribed QoS, which can support the fundamental operations of cellular protocols, must be established for each interface connection. Statistical multiplexing is then limited by the aggregate of the prescribed QoS requirements and only long-term re-configurations, e.g., in response to deployment changes, can optimize the back-haul transmissions. Present wireless network deployments based on the 3GPP LTE standard do not provide feedback from the eNBs to a central decision entity, e.g., an SDN orchestrator, which could flexibly allocate network resources based on eNB traffic demands. Thus, present wireless back-haul architectures are characterized by (i) essentially static network resource allocations between eNBs and operator gateways, e.g., LTE Servicing/Packet Gateways (S/P-GWs), and (ii) lack of coordination between the eNBs and the operator gateways in allocating these network resources, resulting in under-utilization of the backhaul transmission resources. Additionally, exhaustion of available ports at the operator gateways can limit the eNB deployment in practice.
The static resource allocations and lack of eNB-gateway cooperation are highly problematic since the aggregate uplink transmission bitrate of the small cells within a small geographic area, e.g., in a building, is typically much higher than the uplink transmission bitrate available from the cellular operators. Thus, small cell deployments create a bottleneck between the eNBs and the operator gateways. For instance, consider the deployment of 100 small cells in a building, whereby each small cell supports 1 Gbps uplink transmission bitrate. Either each small cell can be allocated only one hundredth of the operator bitrate for this building or the operator would need to install 100 Gbps uplink transmission bitrate for this single building, which would require cost-prohibitive operator gateway installations for an organization with several buildings in a small geographical area. However, the uplink transmissions from the widespread data communication applications consist typically of short high-bitrate bursts, e.g., 100 Mbps bursts. If typically no more than ten small cells burst simultaneously, then the eNBs can dynamically share a 1 Gbps operator uplink transmission bitrate. An additional problem is that with the typically limited port counts on operator gateways, connections to many new small cells may require new operator gateway installations. An intermediate Sm-GW can aggregate the small cell connections and thus keep the required port count at operator gateways low.
It is with these observations in mind, among others, that various aspects of the present disclosure were conceived and developed.
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